The revelations come just a day after the Scottish Prison Service admitted it had to improve the assessment process for the transfer of prisoners to open conditions.

And they have led one senior politician to call for a “significant tightening-up” at the under-pressure jail, whose governor was recently promoted despite rocketing levels of absconding and other concerns.

According to the Scottish Prison Service’s figures, unauthorised items were recovered in the prison, its grounds or outbuildings on 226 occasions in 2007.

That compares with a total of 200 the previous year and just 116 in 2005.

Last year’s tally included 71 recoveries of suspected drugs.

In two incidents, one in the Murray House accommodation block and another in the Wallace wing, the stash included five separate items thought to be narcotics.

MSP Bill Aitken, convener of the Holyrood justice committee, said, “This is unacceptable.

“I know it is difficult for the Scottish Prison Service to guarantee 100% there is no admission of drugs into prisons, particularly open prisons.

“However, we cannot accept a situation where this amount of drugs and other contraband is able to get into the buildings.”

A Scottish Prison Service spokesman said unauthorised items found on prisoners were dealt with by internal ‘Governor report’ procedures.

“All unknown substances and suspected drugs were passed to the police for disposal and/or further action to be taken,” continued the spokesman.

“Unknown substances or suspected drugs found on prisoners which are confirmed as controlled substances by the police are dealt with by the police authorities.”

Forbidden property can include also items such as copied DVDs, and all discs or computer games brought back from home leave are checked by prison security staff.

There are also limits on possessions including toiletries, electrical items, clothing, bedding, jewellery and even posters — including a ban on sectarian or pornographic images.

SPS policy states any failure to adhere to the permitted articles in use list will result in disciplinary action.

Mr Aitken said he believed there had to be a “significant tightening-up all round” at the prison in light of the contraband figures.

“Clearly the SPS will say they’re finding a great deal of stuff, which is fair enough, but the question I would have to ask is what is the extent of other items that they don’t get hold of? It’s very worrying.”

The SPS yesterday published the findings of a review ordered by the Government after a prisoner raped a schoolgirl while on the run from Castle Huntly.

The report stated that the prisoner concerned, Robert Foye, had gone on the run from the Carse jail on a previous occasion because he had been under pressure to engage in drug-taking.

Foye, who has a background of alcohol, drug and solvent abuse from the age of 11, failed a drug test a month before he went on the run again and committed the violent crime.

There was further evidence of the drugs problems within Castle Huntly presented during a court case in Dundee yesterday in which two men admitted absconding.

The pair said that their flight was prompted by illicit substances in the jail.

One claimed Castle Huntly provided his introduction to heroin.